(PECL solr >= 2.2.0)
SolrQuery::addGroupSortField — Add a group sort field (group.sort parameter).
Allow sorting group documents, using group sort field (group.sort parameter).
fieldField name
orderOrder ASC/DESC, utilizes SolrQuery::ORDER_* constants
Example #1 SolrQuery::addGroupSortField() example
<?php
$solrQuery = new SolrQuery('*:*');
$solrQuery
->setGroup(true)
->addGroupSortField('price', SolrQuery::ORDER_ASC);
echo $solrQuery;
?>
The above example will output something similar to:
q=*:*&group=true&group.sort=price asc